On September 19, the last unit of the Shandong Wendeng Pumped Storage Power Station, Unit 6, in which China Railway 14th Bureau Group participated in construction, was officially put into commercial operation, marking the full commissioning of the largest installed-capacity pumped storage power station in Shandong Province and the first in the Jiaodong region. It will strongly guarantee the safe and stable operation of the Shandong power grid, effectively promote energy conservation and emission reduction, and help achieve the "dual carbon" goals.

Six generator units in the power station powerhouse

The Shandong Wendeng Pumped Storage Power Station is located in Wendeng District, Weihai City. It is a key project of Shandong Province's 13th Five-Year Plan and the replacement of old growth drivers with new ones, with a total installed capacity of 1.8 million kilowatts. It is equipped with six mixed-flow reversible pumped storage units and has a designed annual power generation of 2.7 billion kilowatt-hours, enough to supply 1.06 million households for one year. After the station is fully put into operation, it is expected to save 132,300 tons of standard coal and reduce carbon dioxide emissions by 311,200 tons annually.

China Railway 14th Bureau Group is mainly responsible for the civil works and metal structure installation of the water conveyance and power generation system for all six units, including the water diversion, powerhouse, and tailrace systems with three water conveyance tunnels. The overall layout of the contracted works is compact, the structural forms are complex and varied, and the precision requirements and safety risks are high.

Early-stage construction drawing of the underground powerhouse

The underground powerhouse project is the core control project of the Wendeng Pumped Storage Power Station. It is 214.5 meters long, 26.5 meters wide, and 53.5 meters high, equivalent to the height of nearly 20 stories, and is an exceptionally large cross-section cavern.

Power station under construction

During excavation, in order to ensure that the powerhouse cavern is "formed in one pass" and to minimize blasting damage to the surrounding rock, the project department continuously optimized the excavation process, adopting smooth blasting and pre-splitting blasting for cavern excavation, and for the first time innovatively introduced non-blasting cutting technology to improve the excavation quality and stability of the high side walls of the powerhouse.

"Wendeng" TBM

The cavern tunnels of the power station need to pass through seven turns and cross eight faults, making the route very complex. To this end, the project department introduced the world's first compact hard-rock TBM with an ultra-small turning radius, the "Wendeng," for tunnel excavation, filling a gap in the industry and setting multiple records in the construction of domestic pumped storage power stations.

During construction of the water diversion system, the geological structure of the entire waterway system is complex, continuously crossing relatively large faults, and placing high demands on consolidation grouting and fault excavation support technology. Among them, the slopes of the upper and lower inclined shafts of the water diversion line reach as much as 55 degrees. To this end, the project department adopted the "raise boring machine + directional drilling" construction technique in the inclined shaft construction, which solved deviations caused by factors such as magnetic fields and improved excavation construction safety.

Upper reservoir of the power station

During construction, the project department actively summarized work experience and applied for scientific and technological achievements. It has successively applied for 14 authorized patents, including "A Method for Calculating the Initial Support Forces of TBM Tunnels Considering Time Effects," 3 provincial- and ministerial-level construction methods, and published 15 papers, providing experience and guidance for similar construction and becoming a shining calling card for the company's pumped storage power station sector.

In June 2023, all construction tasks of China Railway 14th Bureau Group were completed, and the station successfully passed the water filling and drainage tests of all units and all water conveyance pipelines, laying a solid foundation for the successful operation and grid connection of all six units of the power station.

Lower reservoir of the power station

It is understood that the Shandong Wendeng Pumped Storage Power Station is connected to the Shandong power grid via two 500 kV lines and undertakes tasks such as peak shaving, frequency regulation, valley filling, phase regulation, load reserve, and emergency accident reserve for the provincial power grid. It plays the role of a "stabilizer," "regulator," and "balancer" in the new power system, becoming an "energy storage pool" for local consumption of new energy. It further promotes local economic development, helps achieve the "dual carbon" goals, and is of great significance for accelerating the construction of a new power system with new energy as the main body.